Satellite system beam to beam handover

• US 10,128,578 B2
• Filed: 06/03/2016
• Issued: 11/13/2018
• Est. Priority Date: 03/29/2016
• Status: Active Grant

• Current Assignee: Maxar Space LLC (Galileo Parent, Inc.)
• Original Assignee: Space Systems/Loral Incorporated (Loral Space and Communications Incorporated)
• Inventors: Hreha, William, Wharton, Anne Elizabeth
• Primary Examiner(s): Alam, Fayyaz
• Application Number:
  US15/173,083
• Publication Number:
  US 20180006712A1
• Time in Patent Office: 893 Days
• Field of Search: 455 301- 306, 4555501, 455427-431, 455 7, 455 121, 455 131
• CPC Class Codes: H01Q 21/24 Combinations of antenna units polarised in different directions for transmitting or receiving circularly and elliptically polarised waves or waves linearly polarised in any direction circularly polarised patch antennas H01Q9/0428; circularly polarised horns H01Q13/0241; cross-polarised horns H01Q13/0258; polarisation converters H01Q15/242; cross-polarised rear feeds H01Q19/136; crossed polarisation dual antenna H01Q25/001
• CPC Class Codes: H01Q 3/2682 Time delay steered arrays
• CPC Class Codes: H04B 7/043 using best eigenmode, e.g. beam forming or beam steering
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system
• CPC Class Codes: H04B 7/18515 Transmission equipment in satellites or space-based relays
• CPC Class Codes: H04B 7/18519 Operations control, administration or maintenance
• CPC Class Codes: H04B 7/18521 Systems of inter linked satellites, i.e. inter satellite service for optical links between satellites H04B10/118
• CPC Class Codes: H04B 7/18523 Satellite systems for providing broadcast service to terrestrial stations, i.e. broadcast satellite service arrangements specially adapted for satellite broadcast receiving H04H40/90; picture transmission via satellite H04N1/00103; television transmission via satellite H04N7/20
• CPC Class Codes: H04B 7/18534 for enhancing link reliablility, e.g. satellites diversity
• CPC Class Codes: H04B 7/18541 for handover of resources
• CPC Class Codes: H04B 7/18547 for geolocalisation of a station position fixing by direction or distance determination G01S5/00
• CPC Class Codes: H04B 7/18578 Satellite systems for providing broadband data service to individual earth stations for selecting H04W; provisions for broadband connection, H04Q11/0478
• CPC Class Codes: H04B 7/18584 Arrangements for data networking, i.e. for data packet routing, for congestion control data switching networks H04L12/00
• CPC Class Codes: H04B 7/18595 Arrangements for adapting broadband applications to satellite systems
• CPC Class Codes: H04B 7/19 Earth-synchronous stations
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 56/0015 one node acting as a reference for the others
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/046 the resource being in the space domain, e.g. beams
• CPC Class Codes: H04W 72/21 : in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/23 : in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 84/18 : Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

A satellite communications system provides for handovers between spot beams, including communicating (at a ground based terminal) with a non-geostationary satellite constellation using a first spot beam of the non-geostationary satellite constellation and a first beam hopping plan. The ground based terminal changes the communicating with the non-geostationary satellite constellation to use a second spot beam of the non-geostationary satellite constellation and a second beam hopping plan.

Claims

1. A method for operating a satellite communications system, comprising:

communicating, at a ground based terminal, with respective non-geostationary satellites of a non-geostationary satellite constellation, the ground based terminal using a first constantly moving relative to Earth, spot beam of the non-geostationary satellite constellation and a first time-domain beam hopping plan; and

the ground based terminal changing the communicating with the non-geostationary satellite constellation to use a second constantly moving relative to Earth, spot beam of the non-geostationary satellite constellation and a second time-domain beam hopping plan.

2. The method of claim 1, wherein:

the first beam hopping plan is for a first group of constantly moving relative to Earth, spot beams of a first satellite, where the first group of spot beams includes the first spot beam but does not include the second spot beam; and

the second beam hopping plan is for a second group of constantly moving relative to Earth, spot beams of the first satellite, where the second group of spot beams includes the second spot beam but does not include the first spot beam.

3. The method of claim 1, further comprising:

updating the second hopping plan to account for the ground based terminal changing said communicating with the non-geostationary satellite constellation to use the second spot beam.

4. The method of claim 1, wherein:

the first beam hopping plan is for a first group of spot beams of a first satellite, the first group of spot beams includes the first spot beam and the second spot beam; and

the second beam hopping plan is for the first group of spot beams and accounts for the ground based terminal changing said communicating with the non-geostationary satellite constellation to use the second spot beam.

5. The method of claim 1, wherein:

the first beam hopping plan is for a first group of constantly moving relative to Earth, spot beams of a first satellite, where the first group of spot beams includes the first spot beam; and

the second beam hopping plan is for a second group of constantly moving relative to Earth, spot beams of a second satellite, where the second group of spot beams includes the second spot beam.

6. The method of claim 1, further comprising:

receiving instruction from a gateway via the satellite constellation to change said communicating with the non-geostationary satellite constellation to use a second spot beam of the non-geostationary satellite constellation at a predetermined time.

7. The method of claim 1, wherein:

the ground based terminal changing said communicating includes re-tuning a local oscillator for the ground terminal from a first frequency for the first spot beam to a second frequency for the second spot beam.

8. The method of claim 1, wherein:

the changing said communicating occurring at a handover time;

the communicating with the non-geostationary satellite constellation using the first spot beam includes using a first margin for timing of data communications in a transmit data structure prior to a handover time;

the communicating with the non-geostationary satellite constellation using the first spot beam includes using a second margin for timing of data communications in the transmit data structure near the handover time, the second margin for timing is wider than the first margin for timing; and

the communicating with the non-geostationary satellite constellation using the second spot beam includes using the second margin for timing of data communications in the transmit data structure at the handover time.

9. A satellite communications system, comprising:

a first antenna adapted to communicate with a non-geostationary satellite; and

a processor connected to the first antenna, the processor configured to implement communication with a constantly moving relative to Earth, first spot beam of the non-geostationary satellite using the first antenna and a first time domain beam hopping plan, the processor configured to change said communication to use a constantly moving relative to Earth, second spot beam and a second time domain beam hopping plan.

10. The satellite communications system of claim 9, wherein:

the processor is configured to change said communication by changing communication routing from a first hopping group that includes the first spot beam and not the second spot beam to a second hopping group that includes the second spot beam and not the first spot beam, the first hopping group implements the first time domain beam hopping plan and the second hopping group implements the second time domain beam hopping plan.

11. The satellite communications system of claim 9, wherein:

the second time domain beam hopping plan accounts for movement of the communication from the first spot beam to the second spot beam.

12. The satellite communications system of claim 9, wherein:

the processor is configured to implement communication using the first antenna with the first spot beam of the non-geostationary satellite to communicate with a gateway via the non-geostationary satellite; and

the processor is configured to change said communication to use a another constantly moving relative to Earth, spot beam of the non-geostationary satellite to communicate with the gateway via the non-geostationary satellite.

13. The satellite communications system of claim 9, further comprising:

a second antenna, the processor being configured to change said communication to use the second antenna with the second spot beam to communicate with the non-geostationary satellite.

14. The satellite communications system of claim 9, further comprising:

a second antenna, the processor being configured to change said communication to use the second antenna with the second spot beam to communicate with another satellite.

15. The satellite communications system of claim 9, further comprising:

a second antenna, the processor being configured to change said communication to use the second antenna with the second spot beam to communicate;

a first modem connected to the first antenna and the processor;

a second modem connected to the second antenna and the processor; and

a communication interface connected to the processor.

16. The satellite communications system of claim 9, wherein

the processor is configured to change said communicating at a handover time;

the communication using the first antenna with the first spot beam includes using a narrower margin for timing of data communications in a transmit data structure prior to the handover time;

the communication using the first antenna with the first spot beam includes using a wider margin for timing of data communications in the transmit data structure near the handover time; and

the communication using the second spot beam includes using the wider margin for timing of data communications in the transmit data structure near the handover time.

17. A satellite communications system, comprising:

a first antenna adapted to communicate with a non-geostationary satellite; and

a processor connected to the first antenna, the processor implementing a gateway, the processor configured to communicate with a terminal via the satellite using a first time-domain hopping beam that is constantly moving relative to Earth and a corresponding first time-domain beam hopping plan, the processor configured to instruct the terminal to switch communication to a second time-domain hopping beam that is constantly moving relative to Earth and a corresponding second time-domain hopping plan at a handover time, the processor being configured to send first messages to the terminal via the first time-domain hopping beam for delivery prior the handoff time, the processor being configured to send second messages to the terminal via the second time-domain hopping beam for delivery subsequent to the handoff time.

18. The satellite communications system of claim 17, wherein:

the processor is configured to send the second messages to the terminal prior to the handoff time for delivery subsequent to the handoff time.

19. The satellite communications system of claim 17, wherein:

the processor is configured to determine handover times for the terminal based on location and beam map of the satellite and broadcasts the handover times.

20. The satellite communications system of claim 17, wherein:

the processor is configured to create messages using a first timing margin when not near the handover time; and

the processor is configured to create messages using a second timing margin when near the handover time, the second timing margin is wider than the first timing margin.